IRF1 and gastric cancer: In EBV-associated GC, the PD-L1 expression on tumor cells is triggered by interferon-γ (IFN-γ) via the JAK2/STAT1/interferon regulatory factor-1(IRF1) signaling pathway.401 The EBV nuclear antigen 1 (EBNA1), which is a transcription factor that maintains EBV genome copy number during cell division, may also be a regulator of IFN-γ-induced PD-L1 expression.401 Compared to other GC subtypes, EBV-associated GC displays low expression levels of the PD-L1-targeting miR-200 family, which may also contribute to the high expression of PD-L1.402